Pile fabric treating composition providing soil resistance

ABSTRACT

A durably soil-resistant pile fabric, such as a carpet, is provided which comprises a plurality of organic fibers having thereon a normally solid coating comprising (a) a first phase of a water-insoluble fluoroaliphatic radical free urethane adduct having at least one major transition temperature higher than about 45*C. and melting to a flowable liquid below about 200* C. and (b) a second phase of water-insoluble fluoroaliphatic radical containing urethane adduct having at least one major transition temperature higher than about 45* C. and melting to a flowable liquid below about 200* C.

United States Patent [191 Schultz et al.

[451 July 22, 1975 1 1 PILE FABRIC TREATING COMPOSITION PROVIDING SOILRESISTANCE [75] Inventors: William J. Schultz, White Bear Lake; SamuelSmith, Roseville, both of Minn.

22 Filed: Apr. 2, 1973 21 Appl. No.: 346,838

[52] US. Cl 252/8.75; 252/545; 117/139.5 CQ; 260/29.2 TN

[51] Int. Cl D06m 13/42 [58] Field of Search... 117/139.5 CO, 121, 138.8N; 11/138.8 F; 260/292 TN; 252/875, 545

[56] References Cited UNITED STATES PATENTS 3,398,182 8/1968 Guenthneret a] 252/875 Sweeney et al. 252/875 Groves 252/8.75

Primary Examiner-Stephen J. Lechert, Jr. Attorney, Agent, orFirm-Alexander, Sell, Steldt & DeLal-lunt [57] ABSTRACT A durablysoil-resistant pile fabric, such as a carpet. is provided whichcomprises a plurality of organic fibers having thereon a normally solidcoating comprising (a) a first phase of a water-insolublefluoroaliphatic radical free urethane adduct having at least one majortransition temperature higher than about 45C. and melting to a flowableliquid below about 200 C. and (b) a second phase of water-insolublefluoroaliphatic radical containing urethane adduct having at least onemajor transition temperature higher than about 45 C. and melting to aflowable liquid below about 200 C.

3 Claims, No Drawings 1 FILE FABRIC TREATING COMPOSITION PROVIDING SOILRESISTANCE This invention relates generally to the treatment of pilefabrics, such as upholstery fabrics and carpets with afluoraliphatic-radical-containing component and a component derived fromreactants substantially free of fluorine to impart traffic-durablestain-repellent and soil-resistant properties thereto withoutsignificantly increasing the flammability of the fabric.

The treatment of various textile fabrics with fluorochemicals to impartwater and oil repellency has been known to those in the art for severalyears. For example, various fluorochemical compounds have beenheretofore disclosed for use on textile fabrics made from natural fibersalone, such as wool, cotton, silk, etc., and also for use on textilefabrics made from natural fibers alone or in combination with certainsynthetic fibers, e.g., nylon, polyester and rayon. Variousfluorochemicals have also frequently been used in conjunction withcrease-resistant resins, hand modifiers, water repellents and the liketo improve the fabric performance.

However, treatment with such fluorochemical compounds has not beenuseful or practical for all uses and has been especially impractical fortreating fibers and fabrics which are subjected to severe abrasionduring normal use. For example, the treatment of certain types offibers, e.g., those of poly-(ethyleneterephthalate), with fluorochemicalis often impractical because the fiber surface is not durably receptiveto such fluorochemicals. Thus the fluorochemical may often be removedeasily by abrasion, laundering, dry cleaning, etc. Moreover,conventional fluorochemical treatment of fibers and pile fabrics forcarpet use has been quite impractical because, as a result of the severeabrasion to which such fibers and pile fabrics are subjected, theability to resist soiling and staining is lost after a very short time.

It has been proposed by others, e.g., US. Pat. Nos. 3,068,187;3,256,230; 3,256,231; 3,277,039, and 3,503,915, to mix fluorinatedpolymers with nonfluorinated polymers to obtain a mixture (in a water orsolvent solution or dispersion) which will impart good water and oilrepellency to textiles, paper and leather. As described in thosereferences, by mixing a relatively inexpensive, non-fluorinated polymerwith a fluoroaliphatic-containing polymer, one can obtain a relativelyinexpensive textile fabric or fiber treating mixture which will impartwater and oil repellency to the substrate. for economic reasons, thosepatents suggest using only a minor proportion of the fluoroali phaticpolymer in the mixture, i.e., the non-fluorinated polymer is primarily adiluent in the mixture.

Generally, attempts have been made by others with fluorochemicaltreatments to improve dry soil resistance of substrates, but suchtreatments have not been durable to severe abrasion. Also, treatmentsproposed by others which resist abrasion tend to be receptive to drysoil under conditions of high compressive load. More recently, it hasbecome apparent that prior treatments significantly increase theflammability of fabrics particularly those fabrics having a face pilecomprised principally of synthetic fibers.

In French Pat. No. 2,108,705 it is shown that a coating comprising afluoroaliphatic-radical containing component having at least one majortransition temperature above about 45 C. and a second phase comprising afluoroaliphatic radical free vinylic polymer having at least one majortransition temperature above about 45 C. provided durable soil and stainresistance even under pressure and abrasion.

From the copending application of C. J. Bierbrauer, Ser. No. 218,024,having a common assignee with the instant application it is known thatmore efficient and effective use is made of a soil-resistant coating onpile fabric if the soil-resistant coating is preceded by uniformlyapplied stain repellent coating on the fibers.

In accordance with this invention, there is provided a treated fabriccomprising synthetic fibers having thereon a normally solid coatingcomprising (a) a first phase comprising a water-insolublefluoroaliphatic radical containing urethane adduct containingfluoroaliphatic radical having at least three fully fluorinated carbonatoms and a terminal perfluoromethyl group, and (b) a second phase of awater-insoluble urethane adduct free from fluoroaliphatic radical, bothadducts having at least one major transition temperature higher thanabout 45 C. and melting to flowable liquids at temperatures below about200 C. and at least one of said adducts forming a continuous phase.

The invention also provides novel compositions for the treatment ofcarpets to impart traffic-durable soilresistant and stain-repellingproperties thereto. The compositions comprise at least 0.1% solids in aliquid medium, the solids comprising a water-insoluble component offluoroaliphatic radical containing urethane adduct containing afluoroaliphatic radical comprising at least three fully fluorinatedcarbon atoms and a terminal trifluoromethyl group together with awaterinsoluble component, i.e., urethane adduct free fromfluoroaliphatic radical; both adducts having at least one major thermaltransition temperature higher than about 45 C. and melting to flowableliquids below about 200 C. Generally, the preferred concentration ofpolymers in the composition is about 1% 25% solids, although much higherconcentration, e.g., 50% or more may be useful depending upon the methodused to treat the fibers or fabrics. Although for many purposes anaqueous medium is preferred, for certain purposes, e.g., treatment ofvelvet upholstery fabric, it is useful to employ non-aqueous solutionsor dispersions. Such non-aqueous media include halogenated hydrocarbonssuch as C F Cl and CCl CI-l More specifically, the adducts used arecharacterized as being normally non-rubbery (or curable to a nonrubberystate), non-tacky, normally solid, waterinsoluble, and preferably freeof ethylenic or acetylenic unsaturation. Water-insolubility is requiredto provide durability to the normal cleaning operations such asshampooing. In order to be resistant to soil under high compressiveload, especially particulate soil, the adducts must have at least onemajor transition temperature above about 45 C. which is a melting pointor glass transition temperature in which the polymer becomessignificantly softer as the temperature is raised. Transitions arecharacteristically glass temperature (T or crystalline melting points(T,,,), such as are usually detected by DTA (differential thermalanalysis) or thermo-mechanical analysis (TMA). While suitable materialsmay have, for example, glass transitions at relatively low temperatures,such as 25 C. to 0 C., the adducts must have at least one majortransition point above about 45 C.

As emphasized above, it is critical that the adducts must melt toflowable liquids below about 200 C. Likewise any adjuvants which may beadded must melt to flowable liquid below about 200 C. A flowable liquidis considered to be one which has a viscosity of not over about 200,000centipoises. Materials which char on burning and additives which preventflow, for example, inert fillers, are not operable. It is believed,without wishing to be bound by the theory, that melting and flowingbelow about 200 C. is necessary to allow flow of molten polymer of thefabric, which is believed to decrease the tendency toward burning duringtests or practically.

The fluorinated aliphatic radical R, is a fluorinated, preferablysaturated, monovalent, non-aromatic, aliphatic radical of at least threecarbon atoms. The chain may be straight, branched, or if sufficientlylarge, cyclic, and may be interrupted by divalent oxygen atoms ortrivalent nitrogen atoms bonded only to carbon atoms. It will berecognized by those skilled in the art that such oxygen or nitrogenatoms are chemically screened or masked in the shelter of fullyfluorinated carbon atoms. A fully fluorinated group is preferred, buthydrogen or chlorine atoms may be present as substituents in thefluorinated aliphatic radical provided that not more than one atom ofeither is present in the radical for every two carbon atoms, and thatthe radical must at least contain a terminal perfluoromethyl group.Terminal in the case of a polymer refers to the position in the skeletalchain of the radical furthest removed from the backbone chain.Preferably, the fluorinated aliphatic radical contains not more thancarbon atoms because such a large radical results in inefficient use ofthe fluorine content. The fluoroaliphatic radical containing urethane isthe reaction product of an isocyanate with a fluoroaliphaticradical-containing molecule having one or two isocyanate-reactivehydroxyl groups. The hydroxyl group may be primary, secondary, or lesspreferably, tertiary and is otherwise free of isocyanate reactivegroups. The isocyanatecontaining reactant may have one or moreisocyanate groups which can be attached to an aliphatic (includingcycloaliphatic) or aromatic carbon atom. The exact structure andcomposition of the resulting polyurethane is relatively unimportant, asis the particular molecular weight, which may range from dimer topolymeric polyurethanes having molecular weights up to several hundredthousand or more. The critical requirements are only that the materialcontain at least percent, preferably at least percent by weight ofcarbon-bonded fluorine in the form of fluoroaliphatic radical. that themelting point of the material be above C. and that the material melt toa fluid liquid at temperatures below about 200 C.

Representative fluoroaliphatic reactants for use in forming suitablefluoroaliphatic radical containing urethane adducts include:

0 F so N(CH Those of skill in the art will recognize that mono-ols canbe reacted with diisocyanate to give mono isocyanates or bis-urethanes.

Fluorinated compounds which are employed in the invention include asparticular examples fluoroaliphatic group containing urethanes asdescribed in US. Pat. No. 3,484,281 having melting points above 45 C.and usually up to about 200 C. such as The fluorine free urethane isprepared by conventional means from the same type of isocyanatecompounds used above and from an alcohol or a diol containing primary,secondary or, less preferably, tertiary alcohol and containing one toabout twenty-five carbon atoms, free of other isocyanate-reactivegroups, containing less than 10 percent by weight of halogen,hydrolytically stable. The composition may be a one-toonehydroxyl-isocyanate urethane, or may contain a multiplicity of units inthe form of a polymeric polyurethane substantially free of crosslinks,having a melting point above about 45 C. and melting to a flowableliquid at a temperature below about 200C.

It has been found that both the fluorinated component and the fluorinefree urethane employed must be non-tacky and non-rubbery in order toprevent soil, especially particulate soil, from becoming embedded in thecoating formed by these polymers. It will be recognized that fluorinatedurethanes, as herein used, also possess these characteristics.

It has been found that the fluorinated urethane adduct and the fluorinefree adduct are sufficiently immiscible in, or incompatible with, eachother, that two phases are always formed when these polymers are appliedto a substrate, one of the phases comprises the fluorinated componentand the other phase comprises the fluorine free adduct. Additionally, atleast one of the phases is a continuous phase. Without being bound by aparticular theory, it is believed that a coating, e.g., on a fiber,comprising the fluorinated component and the fluorine-free polymer maycontain, for example, a continuous phase of the fluorinated componentwhile the other is a discontinuous phase of particles dispersedthroughout the continuous phase. Applicants also believe that there maybe two continuous phases, wherein the fluorine free adduct forms a filmon the substrate,

e.g., a fiber, overlain by the fluorinated component or the two may formintergrown networks.

It is preferred that there be a first coating of fluoroaliphatic-radicalcontaining urethane applied to the substrate at 0.05 to 0.2% by weightto face pile fiber (w.f.p.f.) followed by a top coating consistingessentially of a fluorine free urethane together with the same or adifferent fluoroaliphatic radical-containing component in proportions offrom about 1:15 up to about 4:1 at a combined treating weight of 0.1 to0.4% wfpf. The top coating should provide at least about 0.02 percent byweight of carbon-bonded fluorine based on the weight of the face pilefiber.

In treatments of carpet with the procedure of this invention, it ispreferred that a preliminary treatment of e.g. the carpet with thefluoroaliphatic radicalcontaining urethane adduct be made, because thisallows efficient use of the secondary treatment by effectivelyrestricting the treatment to the distal portion of the carpet face pilefibers and particularly the distal 25%. The top spray treatment mustconsist of a mixture of the fluorinated and non-fluorinated adduct. Thepresence of the initial fluorinated adduct coating provides oilrepellency and stain resistance to the total fibre, minimizing travel ormigration of soil or staining material to the carpet backing, from whichit is very difficult to remove. The non-fluorinated component of thetop-coating provides resistance to ground-in soil, while thefluorine-containing component provides pri marily stain resistance.While the ratio of the two components is not critical, if the ratio ofnon-fluorinated to fluorinated is less than about 1:1.75, the dry soilresistance is generally less than desirable. If the ratio is greaterthan about four to one, excessive amounts of top spray must be used toprovide adequate stain resistance, because the minimum amount offluoroaliphatic radical-containing adduct on the fiber in the form oftop spray must contribute at least about 0.02 percent by weight ofcarbon-bonded fluorine of the weight of the face pile fiber. Preferablythe ratio of fluorine-free to fluoroaliphatic radical-containing adductis between about 1.5:] to 4:1.

The top spray solution can be prepared by adding to water a sufficientquantity of fluoroaliphatic radicalcontaining adduct in the form of aconcentrate to provide 1 percent solids of the adduct, and then addingsufficient quantity of a concentrate of the fluorine-free adduct toprovide about 2 percent by weight of adduct solids. Alternatively, andmore conveniently, the two adduct concentrates may be mixed in suchquantities that the ratio of the fluorine-free to fluorine containingadduct solids is between about 1.521 and 4:1. Such a concentrate is auseful commercial embodiment of the invention. This concentrate isdiluted with water to provide a suitable concentration for applicationto carpets.

The four types of carpet which are employed in the following tests aredesignated by the following abbreviations:

cu! pile acrylic CPA loop pile acrylic LPA cut pile nylnn CPN loop pilenylon LPN The method of treatment is to prepad (100% wet pick up) withan aqueous dispersion of 0.1% by weight of solids of the first coatingcomposition conveniently by applying an excess suitably by dipping andthen passing through a squeeze roll to remove the excess. Thispretreated or prepadded sample is then dried at 125 C. and allowed tocool to room temperature before the second coating is applied,preferably by spraying, to about 25% wet pick up or at least an amountsufficient to provide at least 0.02% by weight of carbonbonded fluorinein the weight of the face pile fiber. Treated carpet is again dried,allowed to cool and evaluated for soil resistance by the walk'on test,(AATCCl22-1967 T), water repellency by the AQ test, oil repellency(AATCC 1 18-1966 T), and flammability (DOC FF 1-70) both before andafter shampooing with a commercial carpet shampoo.

The AQ test consists in determining whether a drop of :20 water:isopropanol is absorbed (fail) or not (pass). All samples describedherein passed the test before shampooing and failed afterwards. This isbelieved the result of retention of a residual film of the shampoo underthe conditions used.

The results of the walk-on test were rated visually on a scale of 8 to+8 after 10,000 footsteps and both before and after shampooing.

The standard test for flammability, DOC FF l-70 is carried out by firstconditioning 8 samples approximately 9 inches (23 cm.) square with theparticular treatment by first drying for 2 hours at C. and then placingin a drying cabinet at room temperature for at least one hour. Eachspecimen in turn is then subjected to the actual burning test by firstplacing on it in a draft free area a 0.25 inch (6.3 mm.) thick metalmask of the same outline 9 inch (23 cm.) square as the sample and with acentral circular hole 8 inches (20 cm.) in diameter and then placing atime burning tablet of about 0.149 g. hexamethylene tetramine in thecenter of the hole and igniting it. Burning will spread from the centerpoint depending on flammability. Passing the test for a treated carpetrequires that the charred area in each specimen tested must not comewithin 1 inch (2.5 cm.) of the edge of the metal mask in more than oneof the eight samples tested. A more rigorous test may involve a greaternumber of samples with a smaller percentage being permitted to burn towithin 1 inch (2.5 cm.) of the edge of the mask.

The American Association of Textile Chemists and Colorists (AATCC) testsfor oil repellency 1 l8- 1966T) and the walk-on test (122-1967T) arewellknown and are incorporated by reference.

The invention is now more specifically illustrated by examples showingthe best mode presently contemplated for practicing the invention. Inthese examples, parts are by weight for solids and by volume for liquidsand temperatures are in degrees Centigrade where not otherwisespecified.

EXAMPLE 1 in 16 parts acetone and 48 parts water and 16 parts ofpolyoxyethylene sorbitan monooleate (Tween 80) by putting the totaldispersion through an homogenizer (Manton Gaulin) at 2,500 pounds persquare inch and 75 C. The 45% solid-content emulsion is designatedAdduct D. The solid has a melting point of 110 125C.

Other fluoroaliphatic radical-containing adducts made as described aboveand which can be used in car-.

pet treatments according to the invention include the following:

The emulsion of Adduct D above is used as a first coating by diluting to0.1% solution (weight/volume) with water. Carpet is prepadded to 100%wet pickup as noted above and dried at 125 C.

Fluorine-free urethane adducts are prepared by premixing the desiredalcohols with methyl isobutyl ketone as solvent and dibutyltin dilaurateas catalyst and the diisocyanate is added gradually over about 1 /2hours maintaining the temperature at 80 for a further four hours. Waterdispersions are prepared by dilution with water containing surfactant ina Eppenbach homomixer.

Two non-fluorinated urethane adducts are prepared and emulsified usingthe reactants tabulated below. Numerous other such non-fluorinatedurethane adducts melting to flowable liquids between 45 C. and about 200C. are known and when produced by this or other procedures can beemployed in carpet treatment according to this invention.

-Continued Preparation Adduct A Adduct C isopropyl alcohol 60 g. meltingpoint of adduct 65C. 90C. Emulsification water 240 g. 183 g. Tween (a)7.2 g. 5.3 g. Ethoquad 18/25(b) 7.2 g. 5.3 g.

(a) Trade name for polyoxycthylenl: sorhitan monooleatc (h) Trade namefor polyethoxylatcd quaternary ammonium chloride.

Carpets of various types are prepadded by first padding to 0.1% byweight of face pile fiber (w.f.p.f.) with fluoroaliphatic urethaneAdduct D, and then topcoated with combinations of A plus D and C plus Din the proportions of 2 to 1 respectively of the concentrates by volume,the diluted dispersion containing 3% by weight of urethane solids, andapplied by spray to 25% wfpf wet pickup. The carpets employed are cutpile acrylic, loop pile acrylic, cut pile nylon and loop pile nylon asdescribed above together with loop pile polyester (LPP) and polyestershag (PS). The flammability was tested by the procedure described aboveand they showed no enhanced flammability after testing 24 times. Allpassed the AQ test for water repellency before shampooing and failedafterwards. Oil repellency and walkon tests 10,000 footsteps) aresummarized in the following table.

In contrast to the above, a prepad using a copolymer of C F SO N(CH )CH,O CCl-l=CH and butyl acrylate in :10 proportions followed by topspraying with the combination of adducts A and D gives carpets withincreased flammability (2 out of 8 tests fail). This copolymer softensat about C. anc chars to a brittle solid at higher temperatures.

Failure in flammability tests is also found when this copolymer isemployed in the top spray at 1% concentration in place of Adduct D. Useof a fluorine-free copolymer (in place of Adduct A) of vinylidenechloride, methyl acrylate and itaconic acid, which decomposes to a hardchar at 200, gave 8 failures out of 8 tests. Addition of aluminum oxidemonohydrate to a top spray using Adducts A and D on carpet prepaddedwith Adduct D provides good stain and soil resistance, but failure inthe flammability test in 3 out of 8 samples.

On the basis of these tests, it is concluded that melting to a flowableliquid below about 200C. is a necessary characteristic of each of thecomponents of the carpet treatment.

What is claimed is:

l. A treating solution for rendering pile fabrics stainrepellent andsoil-resistant while avoiding an increase in flammability, consistingessentially of a dispersion in liquid medium at a total solidsconcentration of from about 0.1 to about 50% by weight of thecombination the liquid medium is an aqueous medium.

3. A treating solution according to claim 1 wherein the fluoroaliphaticradical-containing urethane adduct is C6 H3 CH3 in R is alkyl of 1 to 3carbon atoms.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT NO. 3,896 ,035 DATED 3 July 22, 1975 INVENTOM) 1 William J.Schultz and Samuel Smith It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 1, line 50, "for" should read For Column 7, line 67, 0.017 g."should read 0.107 g.

Column 8, line &7, "anc" should read and Signed and Sealed thistwenty-ninth Day of J une1976 [SEALI A ttest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner oflatentsand Trademarks

1. A TREATING SOLUTION FOR RENDERING PILE FABRICS STAIN-REPELLENT ANDOILS-RESISTANT WHILE AVOIDING AN INCREASE IN FLAMMABILITY, CONSISTINGESSENTIALLY OF A DISPERSION IN LIQUID MEDIUM AT A TOTAL SOLIDSCONCENTRATION OF FROM ABUT 0.1 TO ABOUT 50% BY WEIGHT OF THE COMBINATIONOF FLUOROALIPHATIC RADICAL-CONTAINING URETHANE ADDUCT ANDFLUOROALIPHATIC RADICAL FREE URETHANE ADDUCT IN PROPORTIONS OF FROMABOUT 1:1.5 TO ABOUT 4:1 EACH OF SAID ADDUCTS MELTING TO A FLOWABLELIQUID AT ABOVE 45*C. AND BELOW ABOUT 200*C.
 2. A treating solutionaccording to claim 1 wherein the liquid medium is an aqueous medium. 3.A treating solution according to claim 1 wherein the fluoroaliphaticradical-containing urethane adduct is (C8F17SO2NRC2H4OCONH)2 C6 H3 CH3in which R is alkyl of 1 to 3 carbon atoms.